/*
 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 *
 */
package javax.swing.plaf.basic;

import java.awt.*;
import java.awt.event.KeyEvent;
import java.awt.event.FocusEvent;
import java.awt.event.InputEvent;
import java.beans.PropertyChangeEvent;
import java.io.Reader;
import javax.swing.*;
import javax.swing.border.*;
import javax.swing.event.*;
import javax.swing.text.*;
import javax.swing.plaf.*;
import sun.swing.DefaultLookup;

/**
 * Basis of a look and feel for a JTextField.
 * <p>
 * <strong>Warning:</strong>
 * Serialized objects of this class will not be compatible with
 * future Swing releases. The current serialization support is
 * appropriate for short term storage or RMI between applications running
 * the same version of Swing.  As of 1.4, support for long term storage
 * of all JavaBeans&trade;
 * has been added to the <code>java.beans</code> package.
 * Please see {@link java.beans.XMLEncoder}.
 *
 * @author Timothy Prinzing
 */
public class BasicTextFieldUI extends BasicTextUI {

  /**
   * Creates a UI for a JTextField.
   *
   * @param c the text field
   * @return the UI
   */
  public static ComponentUI createUI(JComponent c) {
    return new BasicTextFieldUI();
  }

  /**
   * Creates a new BasicTextFieldUI.
   */
  public BasicTextFieldUI() {
    super();
  }

  /**
   * Fetches the name used as a key to lookup properties through the
   * UIManager.  This is used as a prefix to all the standard
   * text properties.
   *
   * @return the name ("TextField")
   */
  protected String getPropertyPrefix() {
    return "TextField";
  }

  /**
   * Creates a view (FieldView) based on an element.
   *
   * @param elem the element
   * @return the view
   */
  public View create(Element elem) {
    Document doc = elem.getDocument();
    Object i18nFlag = doc.getProperty("i18n"/*AbstractDocument.I18NProperty*/);
    if (Boolean.TRUE.equals(i18nFlag)) {
      // To support bidirectional text, we build a more heavyweight
      // representation of the field.
      String kind = elem.getName();
      if (kind != null) {
        if (kind.equals(AbstractDocument.ContentElementName)) {
          return new GlyphView(elem);
        } else if (kind.equals(AbstractDocument.ParagraphElementName)) {
          return new I18nFieldView(elem);
        }
      }
      // this shouldn't happen, should probably throw in this case.
    }
    return new FieldView(elem);
  }

  /**
   * Returns the baseline.
   *
   * @throws NullPointerException {@inheritDoc}
   * @throws IllegalArgumentException {@inheritDoc}
   * @see javax.swing.JComponent#getBaseline(int, int)
   * @since 1.6
   */
  public int getBaseline(JComponent c, int width, int height) {
    super.getBaseline(c, width, height);
    View rootView = getRootView((JTextComponent) c);
    if (rootView.getViewCount() > 0) {
      Insets insets = c.getInsets();
      height = height - insets.top - insets.bottom;
      if (height > 0) {
        int baseline = insets.top;
        View fieldView = rootView.getView(0);
        int vspan = (int) fieldView.getPreferredSpan(View.Y_AXIS);
        if (height != vspan) {
          int slop = height - vspan;
          baseline += slop / 2;
        }
        if (fieldView instanceof I18nFieldView) {
          int fieldBaseline = BasicHTML.getBaseline(
              fieldView, width - insets.left - insets.right,
              height);
          if (fieldBaseline < 0) {
            return -1;
          }
          baseline += fieldBaseline;
        } else {
          FontMetrics fm = c.getFontMetrics(c.getFont());
          baseline += fm.getAscent();
        }
        return baseline;
      }
    }
    return -1;
  }

  /**
   * Returns an enum indicating how the baseline of the component
   * changes as the size changes.
   *
   * @throws NullPointerException {@inheritDoc}
   * @see javax.swing.JComponent#getBaseline(int, int)
   * @since 1.6
   */
  public Component.BaselineResizeBehavior getBaselineResizeBehavior(
      JComponent c) {
    super.getBaselineResizeBehavior(c);
    return Component.BaselineResizeBehavior.CENTER_OFFSET;
  }


  /**
   * A field view that support bidirectional text via the
   * support provided by ParagraphView.
   */
  static class I18nFieldView extends ParagraphView {

    I18nFieldView(Element elem) {
      super(elem);
    }

    /**
     * Fetch the constraining span to flow against for
     * the given child index.  There is no limit for
     * a field since it scrolls, so this is implemented to
     * return <code>Integer.MAX_VALUE</code>.
     */
    public int getFlowSpan(int index) {
      return Integer.MAX_VALUE;
    }

    protected void setJustification(int j) {
      // Justification is done in adjustAllocation(), so disable
      // ParagraphView's justification handling by doing nothing here.
    }

    static boolean isLeftToRight(java.awt.Component c) {
      return c.getComponentOrientation().isLeftToRight();
    }

    /**
     * Adjusts the allocation given to the view
     * to be a suitable allocation for a text field.
     * If the view has been allocated more than the
     * preferred span vertically, the allocation is
     * changed to be centered vertically.  Horizontally
     * the view is adjusted according to the horizontal
     * alignment property set on the associated JTextField
     * (if that is the type of the hosting component).
     *
     * @param a the allocation given to the view, which may need to be adjusted.
     * @return the allocation that the superclass should use.
     */
    Shape adjustAllocation(Shape a) {
      if (a != null) {
        Rectangle bounds = a.getBounds();
        int vspan = (int) getPreferredSpan(Y_AXIS);
        int hspan = (int) getPreferredSpan(X_AXIS);
        if (bounds.height != vspan) {
          int slop = bounds.height - vspan;
          bounds.y += slop / 2;
          bounds.height -= slop;
        }

        // horizontal adjustments
        Component c = getContainer();
        if (c instanceof JTextField) {
          JTextField field = (JTextField) c;
          BoundedRangeModel vis = field.getHorizontalVisibility();
          int max = Math.max(hspan, bounds.width);
          int value = vis.getValue();
          int extent = Math.min(max, bounds.width - 1);
          if ((value + extent) > max) {
            value = max - extent;
          }
          vis.setRangeProperties(value, extent, vis.getMinimum(),
              max, false);
          if (hspan < bounds.width) {
            // horizontally align the interior
            int slop = bounds.width - 1 - hspan;

            int align = ((JTextField) c).getHorizontalAlignment();
            if (isLeftToRight(c)) {
              if (align == LEADING) {
                align = LEFT;
              } else if (align == TRAILING) {
                align = RIGHT;
              }
            } else {
              if (align == LEADING) {
                align = RIGHT;
              } else if (align == TRAILING) {
                align = LEFT;
              }
            }

            switch (align) {
              case SwingConstants.CENTER:
                bounds.x += slop / 2;
                bounds.width -= slop;
                break;
              case SwingConstants.RIGHT:
                bounds.x += slop;
                bounds.width -= slop;
                break;
            }
          } else {
            // adjust the allocation to match the bounded range.
            bounds.width = hspan;
            bounds.x -= vis.getValue();
          }
        }
        return bounds;
      }
      return null;
    }

    /**
     * Update the visibility model with the associated JTextField
     * (if there is one) to reflect the current visibility as a
     * result of changes to the document model.  The bounded
     * range properties are updated.  If the view hasn't yet been
     * shown the extent will be zero and we just set it to be full
     * until determined otherwise.
     */
    void updateVisibilityModel() {
      Component c = getContainer();
      if (c instanceof JTextField) {
        JTextField field = (JTextField) c;
        BoundedRangeModel vis = field.getHorizontalVisibility();
        int hspan = (int) getPreferredSpan(X_AXIS);
        int extent = vis.getExtent();
        int maximum = Math.max(hspan, extent);
        extent = (extent == 0) ? maximum : extent;
        int value = maximum - extent;
        int oldValue = vis.getValue();
        if ((oldValue + extent) > maximum) {
          oldValue = maximum - extent;
        }
        value = Math.max(0, Math.min(value, oldValue));
        vis.setRangeProperties(value, extent, 0, maximum, false);
      }
    }

    // --- View methods -------------------------------------------

    /**
     * Renders using the given rendering surface and area on that surface.
     * The view may need to do layout and create child views to enable
     * itself to render into the given allocation.
     *
     * @param g the rendering surface to use
     * @param a the allocated region to render into
     * @see View#paint
     */
    public void paint(Graphics g, Shape a) {
      Rectangle r = (Rectangle) a;
      g.clipRect(r.x, r.y, r.width, r.height);
      super.paint(g, adjustAllocation(a));
    }

    /**
     * Determines the resizability of the view along the
     * given axis.  A value of 0 or less is not resizable.
     *
     * @param axis View.X_AXIS or View.Y_AXIS
     * @return the weight -> 1 for View.X_AXIS, else 0
     */
    public int getResizeWeight(int axis) {
      if (axis == View.X_AXIS) {
        return 1;
      }
      return 0;
    }

    /**
     * Provides a mapping from the document model coordinate space
     * to the coordinate space of the view mapped to it.
     *
     * @param pos the position to convert >= 0
     * @param a the allocated region to render into
     * @return the bounding box of the given position
     * @throws BadLocationException if the given position does not represent a valid location in the
     * associated document
     * @see View#modelToView
     */
    public Shape modelToView(int pos, Shape a, Position.Bias b) throws BadLocationException {
      return super.modelToView(pos, adjustAllocation(a), b);
    }

    /**
     * Provides a mapping from the document model coordinate space
     * to the coordinate space of the view mapped to it.
     *
     * @param p0 the position to convert >= 0
     * @param b0 the bias toward the previous character or the next character represented by p0, in
     * case the position is a boundary of two views.
     * @param p1 the position to convert >= 0
     * @param b1 the bias toward the previous character or the next character represented by p1, in
     * case the position is a boundary of two views.
     * @param a the allocated region to render into
     * @return the bounding box of the given position is returned
     * @throws BadLocationException if the given position does not represent a valid location in the
     * associated document
     * @throws IllegalArgumentException for an invalid bias argument
     * @see View#viewToModel
     */
    public Shape modelToView(int p0, Position.Bias b0,
        int p1, Position.Bias b1, Shape a)
        throws BadLocationException {
      return super.modelToView(p0, b0, p1, b1, adjustAllocation(a));
    }

    /**
     * Provides a mapping from the view coordinate space to the logical
     * coordinate space of the model.
     *
     * @param fx the X coordinate >= 0.0f
     * @param fy the Y coordinate >= 0.0f
     * @param a the allocated region to render into
     * @return the location within the model that best represents the given point in the view
     * @see View#viewToModel
     */
    public int viewToModel(float fx, float fy, Shape a, Position.Bias[] bias) {
      return super.viewToModel(fx, fy, adjustAllocation(a), bias);
    }

    /**
     * Gives notification that something was inserted into the document
     * in a location that this view is responsible for.
     *
     * @param changes the change information from the associated document
     * @param a the current allocation of the view
     * @param f the factory to use to rebuild if the view has children
     * @see View#insertUpdate
     */
    public void insertUpdate(DocumentEvent changes, Shape a, ViewFactory f) {
      super.insertUpdate(changes, adjustAllocation(a), f);
      updateVisibilityModel();
    }

    /**
     * Gives notification that something was removed from the document
     * in a location that this view is responsible for.
     *
     * @param changes the change information from the associated document
     * @param a the current allocation of the view
     * @param f the factory to use to rebuild if the view has children
     * @see View#removeUpdate
     */
    public void removeUpdate(DocumentEvent changes, Shape a, ViewFactory f) {
      super.removeUpdate(changes, adjustAllocation(a), f);
      updateVisibilityModel();
    }

  }

}
